1. Field of the Invention
The present invention relates to a stereo-image capturing device that captures images for stereo vision.
2. Description of the Related Art
Stereo vision utilizing a pair of perspective images of a subject is well known in the field of photogrammetric or computer vision engineering. In the stereo vision system, images are taken at different positions so that each of the images has parallax to one another. In the following description, each image for the stereo vision system will be referred to as a parallax image.
There are several methods for capturing parallax images. For example, parallax images may be captured simultaneously by a plurality of cameras or the images may be captured in turn by displacing the position of a single camera. A method for capturing parallax images by a single lens system without displacing the camera position is disclosed in the unexamined Japanese patent publication No. H10-42314. This method uses the principle that when a position of a pinhole is displaced from one place to another on a plane perpendicular to the optical axis, the subject images produced on the imaging surface through the pinhole before and after the displacement have parallax between one another. Namely, a position changeable aperture is utilized in the method. The position of the aperture (pinhole) is displaceable on a plane perpendicular to the optical axis. The position of the aperture is displaced and an image of the subject is captured at each position, so that the parallax images of the subject are obtained. Therefore, by this method, the parallax images can be obtained by using a single lens system and a plurality of cameras or a position changing of a camera is not required. However, the method requires time for capturing the parallax images since each of the parallax images is taken in sequence while moving the position of the aperture.